PRACTICAL OPERATION OF DYNAMOS. 



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parallel. Series generators are seldom used in combination, but 

 when they are so used they are always operated in series. 



The proper division of the total load among a number of shunt 

 generators connected in parallel depends simply upon the adjust- 

 ment of their respective shunt field rheostats. On the other hand, 

 a number of compound gener- 

 ators connected in parallel as 

 shown in Fig. 1 1 1 constitute an 

 unstable system. To obviate 

 this instability and ensure the 

 proper distribution of load 

 among a number of compound 

 generators operating in parallel, 

 the so-called equalizing arrange- 

 ment of connections is used. 



TU- i- - FIg - m ' 



1 his equalizing arrangement 



consists simply of the connection of the series field coils of all 

 the generators in parallel with each other, independently of the 

 parallel connections of the generator armatures, as shown in Fig. 

 1 1 2. Two distinct conditions must be satisfied by the arrange- 



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Fig. 112. 



ment shown in Fig. 1 12 to ensure the proper division of the load 

 among the several generators, namely : 



(a) Each compound generator must be separately adjusted to 

 give the same degree of compounding, by means of a German 



